In situ measurement of temperature and reduction of rutile titania using energy dispersive x-ray diffraction

Using in situ energy dispersive x-ray diffraction (EDXRD) the average specimen temperature of TiO2 in the steady state of flash is experimentally determined. Comparison of the microstructure for flash sintering and conventional sintering in addition to the temperature determined from calibration of the unit cell expansion indicates that rapid Joule heating during flash sintering causes densification and grain growth comparable with conventional sintering. An average temperature approximation model is proposed to account for greybody radiation and thermal conduction. The inhomogeneity of the grain growth across the sample length is confirmed to correlate with inhomogeneity in temperature distribution and this suggests a current induced Peltier effect in n-type TiO2.